Blast or other furnace.



No. 705,822. Pa ten'ted My 29, i902. E. F. corrm.

BLAST 08 OTHER FURNACE.

(Application filed Mar. 27, 1901. Ranewed May 81, 1902.) (lo Model.)

.ZfiezafiOr ELLERY F Col-"FM m: Norms PEYEIYS co. Puomumo. WASHINGTON, c. c

UNITED STATES PATENT OFFICE.

ELLERY F. COFFIN, OF MUIRKIRK, MARYLAND, ASSIGNOR OF ONE-FOURTH TO CHARLES E. COFFIN, OF MUIRKIRK, MARYLAND.

BLAST OR OTHER FURNACE.

SPECIFICATION forming part of Letters Patent No. 705,822, dated July 29, 1902. Application filed March 27,1901. Renewed May 31, 1902. Serial No. 109,809- (No model.)

To all whom it may concern.-

Be it known that I, ELLERY F. CoFEIN, a citizen of the United States, residing at Muirkirk, in the county of Prince George and State of Maryland, have invented certain new and useful Improvements in and Connected with Blast or other Furnaces, of which the follow-- ing is a specification, reference being had therein to the accompanying drawings.

My invention or discovery has reference to an improvement in the art of operating furnaces using a blast of air, such as blast-fu rnaces and-cupolas, its object being to economize in the consumption of fuel and to increase the output, these results being attained by subjecting the blast to an electric discharge, which I believe has the effect of reducing the amount of moisture in the air of the blast.

I have found by actual tests that the invention as applied to a blast-furnace results in a more perfect working of the furnace, an increased production in the metal Within a certain time as compared with the usual method of operation, and, further, in a very great saving in the amount of fuel required, and while I hereinafter describe the invention with special reference to a blast-furnace I desire it to be understood that the invention is equally well adapted for use in all classes of furnaces using a blast of air where elimination of the moisture from the atmosphere and consequent economy of fuel are desired.

It iswell known that all furnaces and fires work or burn better under certain atmospheric conditions than others, and this is especially true of metallurgical furnaces depending upon a blast for their action, and in carrying out my invention I have recognized this factand aim to make permanent the conditions which occasionally in nature cause an improvement in the action of such furnaces, I have discovered that the very best results follow naturally when the air is surcharged with electricity; and it is the object of myinvention to produce artificially this ideal condition' by applying in the use of the invention to a furnace dependent upon a blast e1ec 5o tricity'to the blast, as I have ascertained that the moisture in the blast is thus materially reduced, resulting in more rapid and perfect deoxidation of the ore and a material saving in the proportion of fuel ordinarily required.

In the accompanying drawings I have illustrated the invention in a simple diagram in Figure 1, while Fig. 2 is a detail showing one form of the apparatus employed.

In the diagram Fig. 1 the furnace may represent any form of blast-furnace with its twyers and may also stand as representative of any other form of furnace to which the invention is applicable. The blast-pipe leads from the blower A, of any ordinary or im proved construction and not necessary to be shown or described in detail, and passes to a hot oven, which may also be of any proper construction. From the hot oven the blastpipe leads to the twyers of the furnace. (Not shown.) While I have shown a hot oven, I do not regard this as essential, and I may use this or not, as found desirable and depending on the conditions existing, and my invention contemplates subjecting the blast before or after it enters the hot oven, or both before it enters and after it leaves the oven, to an electric current, or I may omit the hot oven altogether.

At B, I have shown interposed in the blastpipe a tubular non-conducting section composed of any suitable insulating material and capable of withstanding intense heat when used with a hot oven and located between the oven and the furnace.

The generator for the electricity may be of any known or improved type, though I have used successfully a static electrical machine. This, however, it will be understood, is not material and forms no part of my invention.

I have indicated the generators by the words 9:; static electrical machine and by the letter C. One of these machines I have shown as located between the blower and the hot oven, and the other is situated so as to effect the blast as it passes through the insulated tubular section B after it has been heated. The poles of the static machine are indicated at a b, and from these poles connections are made at c (1, extending through the wall of the insulated section B, as shown in detail we enlarged in Fig. 2, and within the section a brush D forms one terminal, while connected to form the opposite terminal is a disk E. The current passes from the brush-points to the disk in the form of a diffused discharge, sometimes called a brush or silent discharge, and the blast as it passes through this space subjected to the action of the current has its moisture removed to a material extent, an analysis showing per cubic meter twenty grams of moisture at the blower and only nine grams after being subjected to the current of electricity. Other analyses showed a greater percentage of moisture removed.

To illustrate conclusively the difference in results by a comparison of the action of the furnace by the ordinary method of operation with the improved method above described, I have taken the results of the best week I have ever made and compared the results with the first week of operation under the new method. The record now given of the results under the old method was made u nder absolutely favorable weather conditionsthat is, a week of dry weather as against a week of wet weather with the new methodand a slightly-richer quality of ore with the old method than with the new, and in spite of this I consumed under the old method eightyfive bushels of charcoal (of twenty pounds to the bushel) to the ton, against seventy-seven bushels of charcoal (of twenty pounds to the bushel) to the ton by the new method. The result in the production was an increase by the new method of two tons and a half for the week, showing a saving of about ten per cent. in fuel. This comparison is made with an exceptional week in the history of the furnace and does not represent the average work of the furnace,which is about ninety-five bushels to the ton and a smaller quantity of iron per day than that stated. It will thus be seen that when compared with the average work of the furnace there is a very large saving in fuel and an increased production of iron, the saving in fuel exceeding fifteen per cent. In both cases, as above given, the percentage of iron in ore did not average over forty-five per cent.

In the treatment of iron by my method the results will be more rapid action, economyin fuel, and a better quality of metal, due to the less quantity of fuel with its impurities.

I wish it to be understood that my invention primarily consists in a process of treating a blast or current of air by passing an electric discharge through it and then passing the air thus treated to the point of use, regardless as to whether this point of use is a blast or other furnace or indeed whether the air be used in connection with a furnace or not, as when once subjected to the discharge the air may be used wherever it may be found of benefit or advantage.

What I claim is 1. The improvement in the art of operating furnaces requiring a blast of air, consisting in drying the air by passing an electric current through it and then forcing the dried air into the furnace, substantially as described.

2. The improvement in the art of operating furnaces requiring a blast of air consisting in drying the air by passing a diffused electric current through it and then forcing the dried air into the furnace, substantially as described.

3. The improvement in the art of operating furnaces requiring a blast of air, consisting in passinga current of electricity throughthe air to eliminate a part of the moisture, heating the air and then passing the dried air to the furnace, substantially as described.

4. The herein-described process of drying a blast or current of air, by passing an electric current through it, and then passing the dry air to the point of use.

5. The process of facilitating the reduction of iron in a blast-furnace, which consists in subjecting to an electric discharge a column of rapidly-moving air under pressure and forcing said air into the furnace.

6. The process hereinbefore described consisting in subjecting a blast or current of air to an electric discharge and then passing the air thus treated to the point of use, substantially as described.

In testimony whereof I affix my signature in presence of two witnesses.

ELLERY F. COFFIN.

Witnesses:

HENRY E. COOPER, JAMES M. SPEAR. 

